东海陆架泥质区沉积有机质的物源分析

色谱和色谱／质谱分析表明，济州鸟西南泥质区正构烷烃、姥鲛烷、植烷、藿烷和甾烷等生物标志物的特征与现代长江口、老黄河口和新黄河口的河流沉积物均区别很大，该泥质区的沉积有机质主要来源于海洋低等生物（如细菌和藻类等）以及陆源高等植物的输入，表现为不同来源和成熟度的生物标志物的混合，同时该泥质区沉积有机质与矿物碎屑沉积物来源不尽相同。长江口泥质区正构烷烃高相对分子质量部分与长江口沉积物相似，正构烷烃和藿烷所反映的有机质成熟度高于现代长江和老黄河口沉积物，甾烷的成熟度与长江相仿而明显高于老黄河口沉积物。长江口泥质区的沉积有机质主要来源于长江输入的陆源高等植物碎片和海洋源的低等生物。东海陆架近岸与远端泥质区沉积有机质的物源很不相同。     

从水体到沉积物:探寻有机质的沉积过程及其意义

自然界中有机质分布广泛、类型多样且性质各异,不论在水体还是在沉积物(岩)中都扮演着重要的角色。因此,探讨各类型有机质聚集和沉积过程的差异性,对深化认识有机质沉积特征和演化规律具有重要的意义。生物体在生长过程中产生了许多有机质,包括生物体自身、生物残体、动物排泄物以及生物分泌的有机分子等,各类型有机质的性质差异极大。由于研究方法的不同,可将海洋中有机质划分为颗粒有机质(particulate organic matter,POM)和溶解有机质(dissolved organic matter,DOM),而DOM又可划分为胶体有机质(colloidal organic matter,COM)和真溶解有机质;从聚合体形式上看,又有海雪和悬浮体等存在形式。进一步分析发现有机质的形态包括生物体、生物残体、排泄物和有机质聚合体等,并且各类型有机质与无机矿物以不同的形式共存。此外,DOM与POM间存在一定的转化关系。这些性质和特征架起了不同类型有机质间聚集和沉积的桥梁。在沉积物(岩)中通过粒度或密度分级分离及孢粉相分析,也发现不同类型的有机质,如生物体、生物残体和无定形等,它们常与特定的无机矿物共生,如无定形多富集在黏粒级颗粒中,而生物体和生物残体多富集在粗颗粒中。进一步溯源发现沉积物(岩)中的各类有机质与生物有机质或海洋中有机质的类型极具相似性,这些特征展现各类型有机质在沉积过程中的差异性。综合有机质的形态、性质以及与矿物共生关系,认为有机质可通过机械沉积、化学沉积和生物沉积等3种不同的方式沉积保存,其中机械沉积的有机质以惰性的生物残体为主,化学沉积的有机质以活性极强的无定形为主,生物沉积有机质以活性较强的微生物和粘附物为主。有机质沉积方式及有机质特征、矿物—有机质间关系和保存条件的差异,决定了有机质的演化命运的不同,进而对有机质生烃以及碳循环产生重要的影响,因而应引起人们的高度关注。     

长江口表层沉积物孢粉相特征及其在碳循环中的意义

选自长江口F2-F5站住的4个表层沉积物及其粒度分级（1～8Ф）样品,经过孢粉相和热解检测,探讨有机质特征及其在碳循环中的命运。未分级样品的孢粉相主要由木质组织、丝炭和黑团块组成,显示陆地输入有机质的贡献巨大。样品分级后,孢粉相面貌发生显著变化。细粒的8函中无定形为主,其他粒级（2～7Ф）中主要由结构有机质组成。细粒的...     

陆相湖盆沉积有机质富集机理研究进展

有机质富集机理的研究对于寻找优质烃源岩、评价盆地的含油气远景具有重要的意义,尤其在日益受到人们重视的页岩气、致密气、油页岩等非常规资源的勘探开发影响下,其研究就显得愈来愈重要和紧迫。而有机质富集机理总体研究程度并不高,对于陆相湖盆有机质的研究相对更为薄弱。以陆相湖盆为研究对象,开展大量国内外关于有机质富集机理的调研,从有机质的生产、有机质分解与保存、有机质的稀释作用三个方面系统总结了陆相湖盆有机质富集的控制因素,并对湖泊与海洋有机质形成的差异性进行了对比分析。研究表明,湖盆有机质的生产受地区光照率、营养盐供给、湖盆地貌、气候环境、湖泊水介质条件、藻类季节性勃发、自养型细菌等的影响;有机质分解与保存受水体分层、细菌生物、无机矿物、水介质条件、黏土矿物、沉积速率等的影响;有机质的稀释作用受沉积速率的影响,并最终得出湖盆中有机质的含量实际上是“有机质生产-有机质分解-有机质稀释”三者相互作用的结果。提出今后值得进一步关注和亟待深入研究的两个方向:自养型细菌在何种环境条件下可以创造高有机质生产力以及不同的水介质条件对有机质分解与保存的影响。     

沉积有机质的喇曼光谱研究

本文用激光喇曼光谱显微探针研究了选自广西、湖南和New Caldeonin（澳大利亚）的11个有代表性沉积变质岩样品中的沉积有机质。有机质有两个主要喇曼频率振动区域:1600cm-1峰和1350cm-1峰。文中对这两个特征喇曼谱峰的归属进行了说明,讨论了不同类型沉积有机质特征喇曼谱峰的差异和不同变质演化阶段有机质产生的喇曼光谱系统性变化规律,指出激光喇曼光谱显微探针技术是一种研究沉积有机质特征十分便利、有效的方法。     

广西百色盆地古近系沉积特征及其古气候意义

通过研究广西百色盆地地表斩龙颈剖面、百东河剖面、六吜剖面、那周剖面记录的沉积特征、沉积标志、粘土矿物组合类型及CaCO3指数的古气候信息,再结合ESR测年数据,确定了古近系古新统晚期六吜组一始新统晚期百岗组(63.1～33.7MaBP)地层时间序列,反应该区自晚古新世至始新世晚期气候由半干早、干旱—潮湿(偏凉)—温暖潮湿—潮湿(偏热)—温暖潮湿向偏干转化的6个古气候演变阶段。     

有机质、粘土矿物吸附和释放金的实验研究及地质意义

有机质、粘土矿物吸附和释放金的实验研究表明：有机质对金的吸附量是粘土矿物的６．８９倍,粘土矿物的混入降低了有机质对金的吸附和释放能力,在低于３００℃的加热条件下,有机质及粘土矿物释放金的能力较低。由实验结果理论推算出太阳顶群的板岩所提供的金量对拉尔玛金矿床的形成是微不足道的,不是该矿床的主要矿源层。     

有机质、粘土矿物吸附和释放金的实验研究及地质意义

有机质、粘土矿物吸附和释放金的实验研究表明：有机质对金的吸附量是粘土矿物的６．８９倍，粘土矿物的混入降低了有机质对金的吸附和释放能力，在低于３００℃的加热条件下，有机质及粘土矿物释放金的能力较低。由实验结果理论推算出太阳顶群的板岩所提供的金量对拉尔玛金矿床的形成是微不足道的，不是该矿床的主要矿源层。     

澄湖SC7孔沉积物粘土矿物特征及其古地理意义

苏州澄湖湖底残留有一条NNW—SSE延伸且已被淤平的古河道。通过对湖心区古河道段SC7孔沉积物的粘土矿物XRD分析及与湖底硬粘土（Q3）、湖岸区沉积（Q4）和长江口滩地现代沉积的比较,表明古河道充填沉积中的粘土矿物主要为伊利石,其次为高岭石、绿泥石、蛭石,还有少量蒙皂石及蛭石/绿泥石混层矿物;其中的伊利石和绿泥石含量均明显偏高,高岭石含量则偏低,伊利石结晶度也较高。粘土矿物组合兼具太湖流域地带性粘土矿物和长江口沉积物的特点,表明古河道充填沉积既有来自本流域表层物质和澄湖扩大过程中的湖岸崩积,也受到长江物源的影响。这一沉积过程也说明古河道在最大海侵时涨潮流和洪水引起海水和江水的频繁倒灌,直至淤塞和淹废。     

Microstructure Evolution of Organic Matter and Clay Minerals in Shales with Increasing Thermal Maturity

As the two important components of shale, organic matter(OM) and clay minerals are usually thought to strongly influence the hydrocarbon generation, enrichment and exploitation. The evolution process of OM and clay minerals as well as their interrelationship over a wide range of thermal maturities are not completely clear. Taking Yanchang(T_3y), Longmaxi(S_1l) and Niutitang(?_1n) shales as examples, we have studied the microstructure characteristics of OM and clay minerals in shales with different thermal maturities. The effects of clay minerals and OM on pores were reinforced through sedimentation experiments. Using a combination of field emission scanning electron microscopy(FESEM) and low-pressure N_2 adsorption, we investigated the microstructure differences among the three shales. The results showed that both OM and clay minerals have strong effects on pores, and small mesopore(2–20 nm) is the dominant pore component for all three samples. However, the differences between the three samples are embodied in the distribution of pore size and the location. For the T_3y shale, clay minerals are loosely arranged and develop large amounts of pores, and fine OM grains often fill in intergranular minerals or fractures. Widespread OM pores distribute irregularly in S_1l shale, and most of the pores are elliptical and nondirectional. The ?_1n shale is characterized by the preferred orientational OM-clay aggregates, and lots of pores in the composites are in the mesopore range, suggesting that over maturity lead to the collapse and compaction of pores under huge pressure of strata. The results of the current research imply that with increasing thermal maturity, OM pores are absent at low maturity(T_3y), are maximized at high maturity(S_1l) and are destroyed or compacted at over-mature stage(?_1n). Meanwhile, clay minerals have gone through mineral transformation and orientational evolution. The interaction of the two processes makes a significant difference to the microstructure evolution of OM and clay minerals in shale, and the findings provide scientific foundation in better understanding diagenetic evolution and hydrocarbon generation of shale.     

陆架边缘海沉积物有机碳矿化及其对海洋碳循环的影响

边缘海沉积物是海洋重要的碳储库,其内部的碳循环主要是由有机质矿化分解过程来驱动的。有机碳进入边缘海沉积物后,矿化分解为溶解无机碳(DIC)进入沉积物孔隙水并扩散到上层水柱,参与海洋系统碳循环;同时还有部分DIC与钙镁等离子结合形成自生碳酸盐,保存于沉积物碳库。从生物地球化学角度探讨有机质埋藏机制和效率,在此基础上重点综述沉积物硫酸盐还原、产甲烷和甲烷厌氧氧化过程的耦合机制,以及有机质矿化对自生碳酸盐形成的影响等方面的研究进展,以期加深对陆架边缘海沉积物在全球碳循环收支平衡中的作用及其气候环境效应的认识。     

Sedimentary Organic Carbon Mineralization and Its Contribution to the Marine Carbon Cycle in the Marginal Seas

Continental margin sediments are important ocean carbon repository, and the internal carbon cycle is mainly driven by the mineralization processes of sedimentary organic matter. Most organic carbon is transformed to Dissolved Inorganic Carbon (DIC) by mineralization processes after being delivered to continental margin sediments, and DIC from pore water diffuses into the upper water column and participates in the ocean carbon cycle. At the same time, some DIC combines ions such as Ca²⁺ and Mg²⁺ and precipitates as authigenic carbonate minerals so that carbon is stored in the deposits. Based on the biogeochemical study of the mechanism and efficiency of organic matter burial, we discussed the interaction among sulfate reduction, methanogenesis and anaerobic oxidation of methane, and the effect of organic mineralization on the formation of authigenic carbonate. By reviewing the above-mentioned aspects, we can obtain a better understanding of the role of continental margin sediments in the global carbon cycling budgets as well as its climate and environmental effects.     

巢湖北部地区海相地层黏土矿物特征及其地质意义

对巢湖北部地区以碳酸盐岩为主的寒武系—下三叠统海相地层的黏土矿物分析及伊利石结晶度测定的结果表明:伊利石是本区海相地层的主体矿物,平均体积分数为73%。黏土矿物的成岩转化特征表现为蒙皂石的伊利石化。按照伊利石结晶度的成岩-浅变质程度划分,本区寒武系—下三叠统的成岩作用已达到最高成岩阶段。伊利石结晶度的纵向变化总体上可分为上、下两部分:下部寒武系至志留系的结晶度为0.41～0.60°Δ2θ,结晶度与埋深具有一定的相关性,成岩作用是下部地层黏土矿物特征的主控因素;上部泥盆系至下三叠统的结晶度为0.45～0.77°Δ2θ,呈波动变化,蒙皂石连续出现,地层没有被显著埋藏,沉积因素是上部地层黏土矿物特征的主控因素。下三叠统地层中蒙皂石的分布特征以及上泥盆统五通组顶部高岭石的普遍富集具有重要的古气候研究意义。     

The Effect of Organic Carbon-Iron Oxide Association on the Preservation of Sedimentary Organic Carbon in Marine Environments

Understanding the mechanisms responsible for long-term storage of organic carbon (OC) in marine environment is important for studying the marine carbon cycling and predicting how the global carbon cycle will respond to climate change. It is estimated that more than 20% of the OC in marine sediments is associated with iron oxides and thus these complexes are one of the most important factors in the long-term storage of OC. The OC-iron oxide (OC-Fe) association can be formed through either adsorption or co-precipitation, but the dominant mechanism of OC-Fe association in marine environments is co-precipitation. The combination of OC from different sources with iron oxides is selective. Iron oxides preferentially combine with marine OC in most marine environments, but in estuarine delta regions they prefer terrestrial OC. Due to large inputs of terrestrial materials, high primary production and frequent re-suspension, estuarine and marginal seas are suitable sites for OC-Fe association studies, which should be emphasized in the future.     

宣城地区龙潭组页岩沉积环境与有机质富集

安徽宣城地区上二叠统龙潭组海陆过渡相页岩不仅是我国下扬子区重要的烃源岩,也是目前我国页岩气勘探的重要层位之一.为研究海陆过渡相页岩沉积环境与有机质富集的关系,以港地1井和两个露头剖面为研究对象,系统开展了有机地球化学测试、有机岩石学研究、氩离子抛光—扫面电镜观察、元素地球化学分析等工作.结果表明:下扬子宣城地区龙潭组页...     

沉积盆地有机质自由基热演化特征及其作为古温标的探索

恢复沉积盆地热历史的方法主要有古地温指标法和动力学模拟法两类.古温标法中最常用的为有机质成熟度和矿物裂变径迹,动力学模拟法中最常用的是盆地的拉张模型和挤压模型.本文针对Ⅰ型有机质自由基浓度作为沉积盆地古温标进行了探索研究.分析了自然演化系列Ⅰ型有机质的自由基的热演化特征;根据自然演化系列的Ⅰ型有机质自由基浓度及时间-温度指数(TTI)数据,对热模拟实验下的Ⅰ型有机质自由基浓度及时间-温度指数(TTI)值进行校正,由校正后的数据初步建立了Ⅰ型有机质的自由基浓度(Ng)与时间-温度指数(TTI)的定量模型.     

有机酸对致密砂岩中黏土矿物的选择性溶蚀研究

提升致密背景下相对优质储层预测的能力,是当今油气勘探开发理论亟待破解的瓶颈和难题。致密油气储层的非均质性强,黏土矿物含量高且是吸附油接触最多的矿物之一。有机酸对黏土矿物的溶蚀影响,是实现致密油高效开采的关键。本文选择鄂尔多斯盆地三叠系延长组为研究对象,通过有机酸与砂岩的溶蚀模拟实验,对实验产物进行pH值、阳离子检测、孔隙度和渗透率测试以及扫描电镜观察。探讨了时间、温度和不同有机酸类型对黏土矿物的溶蚀影响。实验结果显示：①随时间的增长（1~9d）,孔隙度增幅呈先增长后降低的趋势,渗透率的增幅呈持续增长趋势;温度升高（80~95℃）对有机酸溶蚀致密砂岩中的黏土矿物具有促进作用;②不同类型的有机酸对黏土矿物具有选择性溶蚀作用。酒石酸溶蚀大量黏土矿物、碎屑长石以及少量方解石胶结物;乙酸则相反,主要溶蚀方解石;甲酸、乙酸和丙酸配比的合酸以及甲酸、乙酸、丙酸和酒石酸配比的合酸溶液,均优先溶蚀绿泥石化、泥化的长石和方解石,直至方解石完全溶解;③不同类型的有机酸对储层物性的改造能力不同,甲酸对孔隙度的改善不明显,乙酸和丙酸对孔隙度改善明显,合酸对孔隙度的影响是单一酸改善的综合反映。综合分析,有机酸流体与致密砂岩的溶蚀反应机理主要为两种：①有机酸流体提供氢离子,溶蚀致密砂岩中的易溶矿物;②有机酸直接与致密砂岩矿物发生络合反应,影响络合物稳定性的因素主要是有机酸种类和pH值。乙酸、甲酸、丙酸和酒石酸等不同类型的有机酸对致密砂岩中黏土矿物的选择性溶蚀,对储层物性影响程度不一致。     

The Diversity of Organic Matter in Marine Sediments and the Suspiciousness of Source Parameters: A Review

There are various types of Organic Matter (OM) in marine sediments, and it is of great significance to accurately estimate the source of them. The methods used in most researches include element ratio (C/N), stable isotopes (δ¹³C) and biomarkers (BIT), all of which are used for the whole sample as objects and calculated by end-member of terrestrial and marine source OM, respectively. However, OM is preserved in different ways, such as on its own recalcitrance or combining with inorganic minerals. Preservation differences make their respective parameter values change. After differential sedimentary by gravity or other factors,different preservation types of OM are enriched or dispersed, making some parameters distorted and even meaningless in some areas. Therefore, the parameters of OM measured by the whole sample are influenced by the source of OM and the way of deposition and preservation. Therefore, it is unreliable to use these parameters to study the source of OM without considering the way of preservation. Based on this, this paper put forward a method of particle separation to separate the sediment in different propertied and preservation types. According to the composition and characteristics of the OM at the specific grain level, the corresponding index and end-members value were used to calculate more accurate proportion of the OM. It is of profound significance to understand the production, aggregation, occurrence, migration and deposition of OM and its evolution in the entire carbon cycle.     

粘土矿物对有机质生烃的催化作用

烃源岩的有机质主要以有机粘土复合体的形式存在。有机质生烃是一种有机粘土化学反应。反应过程中,有机质与粘土之间存在质子和电子迁移,粘土通过对水分子的吸附和离解为有机质加氢裂解提供H+,而有机质生成的有机酸激活了粘土的催化活性,也为蒙皂石伊利石化反应创造了条件。烃源岩不同粘土矿物的选择性催化特征是影响油气组成的最重要因素。粘土的催化活性大小和发育时间是决定烃源岩生烃潜力大小的因素。由于烃源岩在蒙皂石伊利石化阶段具有最大的催化活性,而且与有机质生烃反应同步,因此富含伊$蒙混合层的烃源岩是世界含油气盆地的最有利烃源岩。不同地质时期的烃类地质储量与烃源岩膨胀性粘土的丰度有密切关系。